Derivative Financial Instruments and Risk Management (Details 5) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Offsetting Assets and Liabilities [Abstract]
Gross Amount of Recognized Assets	$ 170	$ 238
Gross Amounts Offset	0	0
Net Amount of Assets	170	238
Gross Amounts Not Offset, Financial Instruments	(8)	(12)
Gross Amounts Not Offset, Cash Collateral Received	0	0
Net Amount	162	226
Gross Amount of Recognized Liabilities	(9)	(15)
Gross Amounts Offset	0	0
Net Amount of Liabilities	(9)	(15)
Gross Amounts Not Offset, Financial Instruments	8	12
Gross Amounts Not Offset, Cash Collateral Received	0	0
Net Amount	$ (1)	$ (3)